The ToGA trial, an open-label, international, phase III, randomized controlled trial, demonstrated that patients with HER2-positive gastric cancer assigned to receive trastuzumab plus standard chemotherapy had significantly longer overall survival (OS) (hazard ratio: HR 0.74, 95 % CI, 0.60–0.91) compared with patients with HER2-positive gastric cancer assigned to receive chemotherapy alone [7]. Here, ERBB2 is linked to gastric cancer.